[WASM] Missing exported functions on WASM instance

[TrOllOchamO]

Hello, I've been refactoring my project and everything looked fine until I realized that java functions marked with @Export(name = "exportedName") were not attached to the teavm.instance.exports as before.

Since I haven't done anything too suspicious in the code, I suspect it might be due to my modification in the pom.xml. So I was wondering what part of the maven TeaVM dependencies are responsible for the export of the java functions and have I suppressed it by mistake ?

Here is my pom.xml if you see anything obviously missing

```xml 4.0.0 flexio wasm-service 1.0-SNAPSHOT wasm-service io.flexio flexio-service-parent 1.341.0-SNAPSHOT UTF-8 1.8 1.8 4.0.1 0.10.0 3.2.0 flexio-snapshots flexio-snapshots https://mvn.ci.flexio.io/flexio-snapshots/ false true flexio-releases flexio-releases https://mvn.ci.flexio.io/flexio-releases/ true false junit junit test org.teavm teavm-interop ${teavm.version} provided io.flexio.apis.ui.standard.entity.ui flexio-standard-entity-ui-api-types com.github.cliftonlabs json-simple ${json.simple.version} org.teavm teavm-classlib ${teavm.version} provided org.teavm teavm-maven-plugin ${teavm.version} web-client compile ${project.build.directory}/generated/ flexio.Main true true true false FULL WEBASSEMBLY org.apache.maven.plugins maven-dependency-plugin check-dependencies analyze-only true true org.teavm org.apache.maven.plugins maven-resources-plugin ${maven.resources.plugin.version} copy-webapp-resources package copy-resources ${project.build.directory}/site src/main/webapp ${project.build.directory}/generated *.wasm *.js ```

If not, I can provide a repo for you to reproduce :+1: Thanks in advance for your help, --Barnabé

[TrOllOchamO]

Ok, after way too much time I manage to understand the problem, It wasn't caused by a missing pom.xml dependence, but rather how exports works.

I had something like this :

// Main.java
package mypackage;

public class Main {
    public static void main(String[] args) {
    }
}

// Foo.java
package mypackage;

import org.teavm.interop.Export;

public class Foo {
    @Export(name = "bar")
    private static void bar() {
        // does something here
    }
    // ...
}

And when I was calling teavm.instance.exports.bar() on the JS side, I had an error because the exports object did not have any bar function attached. The reason was that I don't use my class Foo anywhere in my java code, so the class was discarded all together, even if it has an exported method attached to it. I bodged this by adding a dummy method to the Foo class and calling it in the main, so the Foo class won't be considered unused anymore.

Like so

```java // Foo.java public class Foo { public satic void init() {} // New // ... } ``` ```java // Main.java public class Main { public static void main(String[] args) { Foo.init(); // ensure TeaVM properly export the bar function } } ```

It works, but it feels like a dirty trick, so I was wondering :

• Is discarding unused methods an intended behavior even when they are marked with @Export ? I feel like functions marked with @Export should always be exported because we are not able to know in advance if the function will be called or not.
• Is there a better way to fix my code ? Is there a way to mark a function to always be exported that I missed ?

Thanks, --Barnabé

[konsoletyper]

Another way to fix the issue is to place all of your exported methods in main class.

Is discarding unused methods an intended behavior even when they are marked with @Export ? I feel like functions marked with @Export should always be exported because we are not able to know in advance if the function will be called or not.

I don't share your feeling. The current behaviour is totally ok.

Is there a better way to fix my code ? Is there a way to mark a function to always be exported that I missed

You can use preservedClasses setting in your build configuration.